How to create Checkout URL if plan/addon ID contains "+" sign?

Problem Statement

My addon ID includes a "+" sign and the Checkout URL throws an error even though the addon exists. Why?

Solution

The "+" character has special meaning in URLs and must be replaced with %2B (URL-encoded form). See URL encoding.

Steps to Set It Up

In any Checkout URL where the plan or addon ID contains a "+" sign, replace + with %2B.

Example: If your addon ID is addon+id and the URL is: https://yoursite.chargebee.com/pages/plans/checkout?addon_ids=addon+id

Change it to: https://yoursite.chargebee.com/pages/plans/checkout?addon_ids=addon%2Bid